The invention relates to a blade, and a holder for that blade, for use in a manual or automated surgical device used for cutting the cornea of the eye and particularly for forming a corneal flap. Several surgical devices are currently available for cutting corneal tissue or a circular flap in the cornea around the pupil of the eye. These devices, commonly referred to as microkeratomes, are placed on the cornea and held in place by suction applied to the periphery of the cornea. A disposable blade is placed into the device and the sharpened edge of the blade is advanced at a precise angle and a predetermined depth into the corneal tissue. The device then provides for a vibrating or oscillating motion to the blade and allows the blade to be moved in a circular, linear, or curvilinear path around the central axis of the microkeratome. This results in the cornea being cut to raise a thin circular layer of anterior cornea with the incision being from about 100 to 200 micron, in depth and about 10 mm in diameter. In a more recent procedure, referred to as LASIK surgery, the circular corneal incision is combined with laser sculpting of a portion of the cornea.
Several microkeratomes are shown in the patent literature. U.S. Pat. No. 5,624,456 covers a device offered by Bausch and Lomb, known as the Hansatome, and U.S. Pat. No. 6,051,009 is directed to blades specifically designed for use in the device shown in the ""456 patent.
Other patents to microkeratomes of different designs are shown in U.S. Pat. Nos. 5,496,339 and 5,658,303 to Koepnick, U.S. Pat. No. 4,884,570 to Krumeich, U.S. Pat. Nos. 5,501,174 and 5,591,174 to Clark et al, U.S. Pat. No. 5,342,378 to Giraud et al, U.S. Pat. No. 6,022,365 to Aufaure et al, U.S. Pat. No. 5,133,726 to Ruiz et al, and U.S. Pat. No. 4,662,370 to Hoffmann et al. All operate in generally the same manner and all require a disposable blade be inserted therein. However, each device requires a different shaped blade and/or blade with blade holder. Therefore, there is a value in having a disposable blade configuration, which may have varied dimensions, which can be assembled with a suitable blade holder for each different device, using the same assembly techniques, so as to provide ease of manufacturing and uniformity of surgical outcome irrespective of the instrument into which the blade or blade assembly is placed.
The invention comprises a blade and a blade assembly wherein the blade has a front, beveled, sharpened edge, and two side edges meeting at a point spaced from the front edge. At least one attachment structure extends from each side edge. A blade holder which extends beyond the side edges, sits on a top surface of the blade and is attached to the blade by a portion thereof which receives the attachment structure. The holder has an opening in an exposed surface to receive an extension from a drive mechanism such that when the drive mechanism is activated the blade is caused to vibrate of oscillate.